This site from the National Council of Teachers of Mathematics has lesson plans, games, brain teasers, and online interactives for learning K-12 math concepts. You can search by grade level, topic or common core standards. Lots of great resources for free!
Saturday Grab Bag
Printable curriculum materials for preschool through second grade levels.
Thursday History/Social Studies
This website from the Government Publishing Office has resources for learning about the US govern
The name of this site says it all!
Tuesday Language Arts
This company provides programs for beginning reading and math learning.
This company publishes three books for helping elementary learners explore science.
Self-paced, online courses for learning coding.